The most common viruses in your body don’t make you ill. Instead, they infect the legions of microbes that live in your gut. These bacteriophages, or phages for short, number in their trillions. And the most common of them might be a newly discovered virus called crAssphage. No one has seen crAssphage under the microscope, but we know what its genome looks like—Bas Dutilh from Radboud University Medical Centre pieced it together using fragments of DNA from the stools of 12 individuals. He found crAssphage in all of them. Then, he found it in hundreds more.
Why Has This Really Common Virus Only Just Been Discovered? – Phenomena: Not Exactly Rocket Science